• 제목/요약/키워드: acd

검색결과 293건 처리시간 0.023초

Buckling analysis of noncontinuous linear and quadratic axially graded Euler beam subjected to axial span-load in the presence of shear layer

  • Heydari, Abbas
    • Advances in Computational Design
    • /
    • 제5권4호
    • /
    • pp.397-416
    • /
    • 2020
  • Functionally graded material (FGM) illustrates a novel class of composites that consists of a graded pattern of material composition. FGM is engineered to have a continuously varying spatial composition profile. Current work focused on buckling analysis of beam made of stepwise linear and quadratic graded material in axial direction subjected to axial span-load with piecewise function and rested on shear layer based on classical beam theory. The various boundary and natural conditions including simply supported (S-S), pinned - clamped (P-C), axial hinge - pinned (AH-P), axial hinge - clamped (AH-C), pinned - shear hinge (P-SHH), pinned - shear force released (P-SHR), axial hinge - shear force released (AH-SHR) and axial hinge - shear hinge (AH-SHH) are considered. To the best of the author's knowledge, buckling behavior of this kind of Euler-Bernoulli beams has not been studied yet. The equilibrium differential equation is derived by minimizing total potential energy via variational calculus and solved analytically. The boundary conditions, natural conditions and deformation continuity at concentrated load insertion point are expressed in matrix form and nontrivial solution is employed to calculate first buckling loads and corresponding mode shapes. By increasing truncation order, the relative error reduction and convergence of solution are observed. Fast convergence and good compatibility with various conditions are advantages of the proposed method. A MATLAB code is provided in appendix to employ the numerical procedure based on proposed method.

Identification and risk management related to construction projects

  • Boughaba, Amina;Bouabaz, Mohamed
    • Advances in Computational Design
    • /
    • 제5권4호
    • /
    • pp.445-465
    • /
    • 2020
  • This paper presents a study conducted with the aim of developing a model of tendering based on a technique of artificial intelligence by managing and controlling the factors of success or failure of construction projects through the evaluation of the process of invitation to tender. Aiming to solve this problem, analysis of the current environment based on SWOT (Strengths, Weaknesses, Opportunities, and Threats) is first carried out. Analysis was evaluated through a case study of the construction projects in Algeria, to bring about the internal and external factors which affect the process of invitation to tender related to the construction projects. This paper aims to develop a mean to identify threats-opportunities and strength-weaknesses related to the environment of various national construction projects, leading to the decision on whether to continue the project or not. Following a SWOT analysis, novel artificial intelligence models in forecasting the project status are proposed. The basic principal consists in interconnecting the different factors to model this phenomenon. An artificial neural network model is first proposed, followed by a model based on fuzzy logic. A third model resulting from the combination of the two previous ones is developed as a hybrid model. A simulation study is carried out to assess performance of the three models showing that the hybrid model is better suited in forecasting the construction project status than RNN (recurrent neural network) and FL (fuzzy logic) models.

Seismic assessment of base-isolated nuclear power plants

  • Farmanbordar, Babak;Adnan, Azlan Bin;Tahir, Mahmood Md.;Faridmehr, Iman
    • Advances in Computational Design
    • /
    • 제2권3호
    • /
    • pp.211-223
    • /
    • 2017
  • This research presented a numerical and experimental study on the seismic performance of first-generation base-isolated and fixed-base nuclear power plants (NPP). Three types of the base isolation system were applied to rehabilitate the first-generation nuclear power plants: frictional pendulum (FP), high-damping rubber (HDR) and lead-rubber (LR) base isolation. Also, an Excel program was proposed for the design of the abovementioned base isolators in accordance with UBC 97 and the Japan Society of Base Isolation Regulation. The seismic assessment was performed using the pushover and nonlinear time history analysis methods in accordance with the FEMA 356 regulation. To validate the adequacy of the proposed design procedure, two small-scale NPPs were constructed at Universiti Teknologi Malaysia's structural laboratory and subjected to a pushover test for two different base conditions, fixed and HDR-isolated base. The results showed that base-isolated structures achieved adequate seismic performance compared with the fixed-base one, and all three isolators led to a significant reduction in the containment's tension, overturning moment and base shear.

Thermo-mechanically induced finite element based nonlinear static response of elastically supported functionally graded plate with random system properties

  • Lal, Achchhe;Jagtap, Kirankumar R.;Singh, Birgu N.
    • Advances in Computational Design
    • /
    • 제2권3호
    • /
    • pp.165-194
    • /
    • 2017
  • The present work proposes the thermo mechanically induced statistics of nonlinear transverse central deflection of elastically supported functionally graded (FG) plate subjected to static loadings with random system properties. The FG plate is supported on two parameters Pasternak foundation with Winkler cubic nonlinearity. The random system properties such as material properties of FG material, external loading and foundation parameters are assumed as uncorrelated random variables. The material properties are assumed as non-uniform temperature distribution with temperature dependent (TD) material properties. The basic formulation for static is based on higher order shear deformation theory (HSDT) with von-Karman nonlinear strain kinematics through Newton-Raphson method. A second order perturbation technique (SOPT) and direct Monte Carlo simulation (MCS) are used to compute the nonlinear governing equation. The effects of load parameters, plate thickness ratios, aspect ratios, volume fraction, exponent, foundation parameters, and boundary conditions with random system properties are examined through parametric studies. The results of present approaches are compared with those results available in the literature and by employing direct Monte Carlo simulation (MCS).

A comparative analysis of sheeting die geometries using numerical simulations

  • Igali, Dastan;Wei, Dongming;Zhang, Dichuan;Perveen, Asma
    • Advances in Computational Design
    • /
    • 제5권2호
    • /
    • pp.111-125
    • /
    • 2020
  • The flow behavior of polymer melts within a slit die is an important consideration when designing a die geometry. The quality of the extruded polymer product can be determined through an evaluation of the flow homogeneity, wall shear rate and pressure drop across the central height of the die. However, mathematical formulations cannot fully determine the behavior of the flow due to the complex nature of fluid dynamics and the nonlinear physical properties of the polymer melts. This paper examines two slit die geometries in terms of outlet velocity uniformity, shear rate uniformity at the walls and pressure drop by using the licensed computational fluid dynamics package, Ansys POLYFLOW, based on the finite element method. The Carreau-Yasuda viscosity model was used for the rheological properties of the polypropylene. Comparative analysis of the simulation results will conclude that the modified die design performs better in all three aspects providing uniform exit velocity, uniform wall shear rates, and lower pressure drop.

Compressive strength prediction of limestone filler concrete using artificial neural networks

  • Ayat, Hocine;Kellouche, Yasmina;Ghrici, Mohamed;Boukhatem, Bakhta
    • Advances in Computational Design
    • /
    • 제3권3호
    • /
    • pp.289-302
    • /
    • 2018
  • The use of optimum content of supplementary cementing materials (SCMs) such as limestone filler (LF) to blend with Portland cement has been resulted in many environmental and technical advantages, such as increase in physical properties, enhancement of sustainability in concrete industry and reducing $CO_2$ emission are well known. Artificial neural networks (ANNs) have been already applied in civil engineering to solve a wide variety of problems such as the prediction of concrete compressive strength. The feed forward back propagation (FFBP) algorithm and Tan-sigmoid transfer function were used for the ANNs training in this study. The training, testing and validation of data during the backpropagation training process yielded good correlations exceeding 97%. A parametric study was conducted to study the sensitivity of the developed model to certain essential parameters affecting the compressive strength of concrete. The effects and benefits of limestone filler on hardened properties of the concrete such as compressive strength were well established endorsing previous results in the literature. The results of this study revealed that the proposed ANNs model showed a high performance as a feasible and highly efficient tool for simulating the LF concrete compressive strength prediction.

Free vibration of Levy-type rectangular laminated plates using efficient zig-zag theory

  • Behera, Susanta;Kumari, Poonam
    • Advances in Computational Design
    • /
    • 제3권3호
    • /
    • pp.213-232
    • /
    • 2018
  • First time, an exact solution for free vibration of the Levy-type rectangular laminated plate is developed considering the most efficient Zig-Zag theory (ZIGT) and third order theory (TOT). The plate is subjected to hard simply supported boundary condition (Levy-type) along x axis. Using the equilibrium equations and the plate constitutive relations, a set of 12 m first order differential homogenous equations are obtained, containing displacements and stress resultant as primary variables. The natural frequencies of a single-layer isotropic, multi-layer composites and sandwich plates are tabulated for three values of length-to-thickness ratio (S) and five set of boundary conditions and further assessed by comparing with existing literature and recently developed 3D EKM (extended Kantorovich method) solution. It is found that for the symmetric composite plate, TOT produces better results than ZIGT. For antisymmetric and sandwich plates, ZIGT predicts the frequency for different boundary conditions within 3% error with respect to 3D elasticity solution while TOT gives 10% error. But, ZIGT gives better predictions than the TOT concerning the displacement and stress variables.

Merging the old with the new: a cybermedicine marriage for oncology interactions with traditional herbal therapies and complementary medicines

  • Yap, Kevin Yi-Lwern;Lim, Ken Juin
    • 셀메드
    • /
    • 제2권2호
    • /
    • pp.18.1-18.16
    • /
    • 2012
  • An oncology-specific database called OncoRx (http://bit.ly/cancerRx) was previously set up in cyberspace to aid clinicians in identifying interactions of anticancer drugs (ACDs) and chemotherapy regimens with traditional Chinese medicines (TCMs) and complementary and alternative medicines (CAMs). Since then, users have requested the drug-CAM interactions (DCIs) of 5 specific CAMs (cranberry, melatonin, co-enzyme Q10, huachansu, reishi mushroom) to be updated in the database. Pharmacokinetic properties (metabolism, enzyme induction/inhibition, elimination), TCM properties and DCIs of each CAM were collated with 117 ACDs using 9 hardcopy compendia and online databases as resources. Additionally, individual ACDs and CAMs were used as keywords for PubMed searches in combination with the terms 'anticancer drugs', 'drug interactions', 'herb-drug/drug-herb interactions', 'pharmacokinetic interactions' and 'pharmacodynamic interactions'. DCI parameters consisted of interaction effects, evidence summaries, proposed management plans and alternative non-interacting CAMs, together with relevant citations and update dates of the DCIs. OncoRx is also used as a case to introduce the "Four Pharmaco-cybernetic Maxims" of quality, quantity, relationship and manner to developers of digital healthcare tools. Its role in Hayne's "5S" hierarchy of research evidence is also presented. OncoRx is meant to complement existing DCI resources for clinicians and alternative medicine practitioners as an additional drug information resource that provides evidence-based DCI information for ACD-CAM interactions.

식이지방과 Tocopherol 첨가가 혈액의 지질 및 조직의 Tocopherol 함량과 지방산조성에 미치는 영향 (Effect of Dietary Fat and Marginal Tocopherol Supplement on Plasma Lipid, Tocopherol Contet and Fatty acid Composition of Rat Tissues)

  • 남정혜
    • Journal of Nutrition and Health
    • /
    • 제19권5호
    • /
    • pp.304-314
    • /
    • 1986
  • To observe the effect of the different level of PUFA and marginal tocopherol supplement on HDL-chol, tissue tocopherol content and fatty acid composition, the rats were supplied either safflower oil or conconut oil with or without tocopherol supplement to the experimental diet. Plasma tocopherol level was not greatly influenced by the different dietary fat and similar effect was observed in the liver but not in the adipose tissue. HDL-chol level was reduced in the high PUFA diet regardless of tocopherol content. No effect by tocopherol supplement was observed in the fatty acid composition of liver and adipose tissue lipid in both dietary PUFA levels . There was also no increase in the content of tissue polyenoid acid by tocopherol in the high PUFA diet . Fatty acid composition of tissue lipid was rather more influenced by dietary fat. Lauric and myristic acid contents were higher in the low PUFA diet and linoleic acd and total polynoic acid content were higher in the high PUFA diet. With tocopherol supplement tocopherol /PUFA ratio of tissue was increased but the ratio of high PUFA diet was significantly lower than that of low PUFA diet. Marginal tocopherol supplement could not reduce the peroxidizability index of high PUFA diet.

  • PDF

개심술 500예에 대한 임상적 고찰 (Clinical experience of open heart surgery -500 cases-)

  • 정황규
    • Journal of Chest Surgery
    • /
    • 제19권4호
    • /
    • pp.633-643
    • /
    • 1986
  • Five hundred cases of open heart surgery were operated in the Dept. of Thoracic and Cardiovascular Surgery, Pusan National University Hospital from July, 1981 to October, 1986. The clinical data were summarized as follows: 1. The age distribution of congenital heart disease patients was 2 to 41 years old and mean age was 13.4 years and of acquired heart disease was 11 to 57 years old and mean age was 32.7 years. 2. There were 319 cases [63.8%] of acyanotic congenital heart anomalies, 56 cases [11.2%] of cyanotic anomalies and 125 cases [25.[%] of acquired heart disease. 3. For myocardial protection, Bretschneider and potassium glucose solution had been used as cardioplegic solution and since 1983, GIK solution is being used repeatedly every 30 to 40 minutes time interval with excellent results. 4. The ingredient of the priming solution is Hartmann`s solution, mannitol, sodium bicarbonate, potassium, chloride, fresh ACD whole blood, calcium chloride, heparin and dexamethasone. 5. There were 94 cases of mild hypothermia, 280 cases of moderate hypothermia and 126 cases of intermediate hypothermia. 6. The overall mortality was 8.2%. And the mortality rate in each disease entity is 2.5% in acyanotic congenital cases, 33.9% in cyanotic congenital cases and 11.2% in acquired heart disease.

  • PDF